Overhaul command permission builders

[kangalio]

• 🔤 Renames CreateCommandPermissionsData builder to EditCommandPermissions
  • Name is more fitting because the builder calls the edit_guild_command_permissions endpoint
• 🔤 Renames CreateCommandPermissionData builder to CreateCommandPermission
• 🔤 Renames CommandPermission model type to CommandPermissions
  • Name is more fitting because it actually stores a Vec of all permissions for a single command
• 🔤 Renames CommandPermissionData to CommandPermission
• 🔤 Renames [GuildId, Guild, PartialGuild]::create_command_permission to edit_command_permission
  • Less misleading - this method overwrites all permissions of the given command
  • Matches the HTTP endpoint name
• ✨ Replaces EditCommandPermissions methods new(), add_permission(CreateCommandPermission), set_permissions(Vec<CreateCommandPermission>) with just new(Vec<CreateCommandPermission>)
  • Not providing any CreateCommandPermission instances makes no sense, and new(vec![a, b, c]) is easier for both serenity and the user than new().add_permission(a).add_permission(b).add_permission(c)
• ✨ Replaces CreateCommandPermissionData methods new(), kind(CommandPermissionType), id(CommandPermissionId), permission(bool) with role(RoleId, bool), user(UserId, bool), channel(ChannelId, bool)
  • Much shorter to invoke
  • Cannot be misused (previously your configured kind could mismatch the type of ID you passed in)
  • Shows everything you can do with a command permission on one glance
• ✨ Adds CreateCommandPermission::everyone(GuildId, bool) and CreateCommandPermission::all_channels(GuildId, bool)
  • These were previously missing
• ❌ Removes edit_guild_commands_permissions endpoint
  • This endpoint has been disabled with Permissions V2 (Discord docs)
  • Don't confuse with edit_guild_command_permissions (note the plural) - that endpoint is still active!
• 🔧 Replaces CreateCommandPermission's inner private fields by making CreateCommandPermission a newtype around CommandPermission
  • They share the same schema in the Discord docs so we can also share the same type struct definition

This PR has not been runtime tested

[kangalio]

Noticing the delay of merging: I made these changes because it makes more sense to do things this way imho - however, as always, I'm not sure if this gain for new code outweighs the churn for existing code. If others believe the breaking change of this PR is not worth it, I'm ok with not having this PR merged.